We are developing system which processes transactions coming from ATM machines of various banks. We take incoming messages to Request Queue, Process it at multiple stages and Send response back to Response Queue which is then sent back to Socket connection established when ATM initiated transaction. I have some questions related to design of this system using ActiveMQ and Camel.
Q1) Do I need a JTA transaction or regular JMS transaction when I move data from one queue to another queue of same broker. Assume no Database is involved and queues are in persistent mode. Since both Queue are associated with same broker so both comes under same Resource Manager, so want to clarify if XA type transaction is involved over here ? Q2) Assume I have 3 stages between Request and Response Queue, each stage might do some data processing like calling a remote service or calling some local api etc. So do I need to keep a SEDA block for each stage or a regular pipeline block will suffice. If I consume aysnchronously from Request queue with some concurrent consumers then I would have already got that many threads to work on those stages so whats the necessity of introducing SEDA stages ?? Also SEDA stages might also complicate jms transaction rollback if any of the stage throws exception. What I want is the data to move from REquest to Response only when all 3 intermediate stages completes otherwise message to be redelivered before sending it to DLQ. Only benefit which I see in using SEDA is that I can declare async concurrent consumers at every stages, but as I mentioned earlier I already have concurrent consumer threads consuming from Request Queue and calling these intermediate Services in pipeline block. Q3) Assuming I need to save intermediate data in database at every stages of processing, we dont want to disturb the main loop of request and response queue bcoz performance is the key in this system, so we thought of sending intermediate data in a separate queue dedicated for just Inserts/Updates. So for every transaction I will send a insert message when it reaches the Request queue and then multiple update messages on completion of each stages. Failure at Database queue should not stop the main loop. So assuming incoming transaction message was pipe delimited text, then I convert it to JPA entity object and send it to DB queue for insert, then after every stage I update this entity object and send it to DB queue which in turn calls EntityManager.merge() to update previously inserted record. Will this work Or we should create entities only after consuming text from DB queue. -- View this message in context: http://camel.465427.n5.nabble.com/transaction-handling-while-moving-data-from-queue-to-seda-to-queue-tp5775247.html Sent from the Camel - Users mailing list archive at Nabble.com.
